首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Summary

Similar experiments in 1984 and 1985 examined the effects of cauliflower transplant age and ‘high’ or ‘low’ nutrient feeding regimes during plant.raising on the numbers of leaves formed, the timing of curd initiation, maturity and other maturity characters. ‘High’ nutrient feed contained 104 mgl?1N and 290 mgl?1K whereas ‘low’ nutrient feed contained 52 mg l?1 N and 145 mg l?1 K. In addition, in 1985 the growth of other ‘low-feed’ plants was boosted by giving them ‘high feed’ during the last four days before transplanting. The raising treatments produced transplants which differed in dry weight, in the numbers of leaves formed and especially in dry-matter percentage. In both years the oldest ‘low-feed’ plants had the highest dry-matter percentage at transplanting (mean 22.2%) whereas the youngest ‘high-feed’ plants had the lowest dry-matter percentage (mean 12.9%). After transplanting, differences between treatments rapidly disappeared and there were few significant effects of treatments on the time of curd initiation, the final number of leaves formed, the time of 50% curd maturity and marketable curd yield. It is concluded that when planning cauliflower continuity schedules the time of transplanting is important but the precise age of plants at transplanting and the feeding regime prior to this need not be taken into account provided plant size is kept within normal limits.  相似文献   

2.
In growth chambers the effect of temperature (12–27°C) on the growth and development of cauliflower cultivars of temperate and tropical climates, as well as of broccoli cultivars, was tested. No difference was found between the cultivars as regards dry matter production and curd growth, but a difference was found in the time of curd initiation. The early cauliflower ‘Aristokrat’ does not form lateral shoots or floral buds before elongation of the inflorescence at any temperature level. This always occurs in broccoli cultivars. The tropical cauliflowers have an intermediate position. At low temperatures (12–17°C) only 12–14 leaves are formed. Many lateral shoots are initiated and a broccoli-like curd with fertile flowers is developed. At high temperatures (22–27°C) the same cultivars produce a considerably higher leaf weight, less lateral shoots are initiated, and a cauliflower-like curd without floral buds is formed.  相似文献   

3.
  相似文献   

4.
Summary

In experiments in 1994 and 1995 a range of transplanting dates and thermal crop covering treatments were used to produce different environmental conditions for the growth of two Roscoff cauliflower selections ‘December/January’ and ‘March’. In 1994 non-covered plants of ‘March’ initiated on average 19 d later and with 19 leaves more than ‘December/January’. In the two seasons, covering the crops gave delays in curd initiation of up to 93 d, depending on planting date, and increased the number of leaves produced by up to 50 compared with non-covered crops. Leaf production was best described by an accumulated effective day-degree scale using day-degrees <17°C for ‘December/ January’ and day-degrees <16°C for ‘March’. This shows that both light and temperature are concerned with controlling leaf production. During the juvenile phase of growth, apex diameters expanded linearly with temperature up to a diameter of about 0.2 mm. After this there was a different response to temperature suggesting that a phase change had occurred at an apex diameter of 0.2 mm. When this occurred numbers of leaves ranged from 23 to 28. Vernalization appeared to occur most rapidly in ‘December/January’ between 12 and 16°C with an optimum at about 14°C while in ‘March’ the optimum appeared to be slightly lower than this. Any increase in time spent at temperatures in excess of 16°C delayed curd initiation.  相似文献   

5.
Summary

The effects of photoperiod, light intensity and temperature on bulb formation and bulb structure of two tropical onion cultivars were investigated. From an initial experiment it was observed that the number of true scales and sheath scales differed significantly between the cultivars ‘Red Creole’ and ‘Agrifound Dark Red’. When these two cultivars were given 11, 12 and 13 h photoperiod treatments, it was found that both cultivars needed at least 12 h photoperiod for bulb formation. Modify the R/FR ratio from 1.22 to 1.16 in the final hour of the 11 h light period did not induce bulbing. The 13 h photoperiod increased the number of true scales and decreased the number of sheath scales compared with the 12 h photoperiod in both cultivars but total scale + leaf sheath numbers remained nearly constant. When onion plants were grown under 0%, 25%, 50% and 75% shading treatments, (12 h photoperiod), only plants receiving 0% and 25% shading bulbed. Low light intensity decreased the number of true scales and increased the number of sheath scales. Four temperature regimes were compared in a growth room experiment. Plants under the 29°348C treatment bulbed within two weeks and matured within six weeks. However, plants receiving the 25°308C treatment delayed bulb initiation more than those plants receiving 17°228C and 21°268C treatments. At the lowest temperature, bigger bulbs with thick necks were produced. This may be due to changes in bulb structure since at low temperature, the number of sheath scales was increased, however the number of true scales remained relatively constant in both cultivars. Dormant leaf initials decreased with decreasing temperature while the number of secondary meristems significantly increased. The results suggest that ‘Red Creole’ was more responsive to shorter photoperiods, bulbing earlier than ‘Agrifound Dark Red’. There was no significant difference in time to bulbing in response to temperature between the two cultivars if measured by bulbing ratio however there were differences in bulb structure which suggested that ‘Red Creole’ bulbed earlier. These effects may be due to the breeding histories of the two cultivars. It is suggested that studying bulb structure may provide a useful method of interpreting onion bulbing responses.  相似文献   

6.
Abstract

Growing fruits and vegetables in plastic tunnels is known to accelerate maturity and protect quality. There are several studies on highbush blueberry (Vaccinium corymbosum) that demonstrate the ability of row covers to advance or delay crop maturity depending on how they are manipulated. Accelerating or delaying harvest time can prove to be very lucrative for producers. However, before producers start putting plastic tunnels over their crops it is important to know how blueberry cultivars will behave when grown under plastic. Six cultivars of southern highbush blueberry and eight cultivars of northern highbush blueberry were grown in a high hoop plastic tunnel for two seasons. Blueberry plants were grown under plastic from February 1 until their harvest was completed each year. After harvest, the plastic covering over the hoops was removed to help the blueberry plants develop fruit buds and meet winter chill requirements. On February 1 the plastic covering was returned to the high hoop tunnel after chilling requirements were met. As expected, fruit maturity dates were 1-3 weeks earlier for all the highbush blueberries grown inside the tunnel versus the same cultivars grown outside. The difference in maturity dates between cultivars grown under plastic and outside did change from one year to the next because of variation in the weather. Despite potential for poor pollination of blueberries in plastic tunnels, yields were significantly enhanced for four cultivars when grown under plastic tunnels. ‘Toro’, ‘Nui’, ‘Legacy’, and ‘Misty’ showed yield gains ranging from 1 to 4 times when grown under a plastic tunnel. Seed numbers per fruit were not significantly impacted by growing plants inside our tunnel.  相似文献   

7.
花椰菜新品种‘浙801’   总被引：2，自引：1，他引：1  
 ‘浙801’是通过‘3045-1’ב955’获得的半松散花椰菜杂交一代,生育期约80 d。植株半直立,生长势强,叶面蜡粉多。花球半圆球形,球径约20 cm,单球质量1 kg以上,花蕾细腻,淡青梗。花球含粗蛋白2.12%,维生素C 625 mg · kg-1,可溶性糖2.71%,可用于脱水加工。适宜华东地区种植。  相似文献   

8.
《Scientia Horticulturae》2001,89(3):237-248
Dormant second year potted plants of Paeonia ‘Coral Sunset’, ‘Monsieur Jules Elie’, and ‘Sarah Bernhardt’ were placed into three chilling regimes (constant 1, 4, or 7°C) for different durations (3, 6, 9, or 12 weeks) to ascertain their chilling requirements for shoot and flower production. Chilling was followed by forcing for up to 5 weeks at 18°C, then plants were maintained in a controlled greenhouse until flowering had finished. Mean number of shoots and flowers per plant were recorded and the time taken for shoots to sprout was calculated.Control plants (forced immediately without chilling) produced no shoots or flowers. For all cultivars, the proportion of plants that sprouted, and the mean number of shoots and flowers increased as plants were subjected to colder chilling temperatures, or longer chilling durations. However, there were no significant within-cultivar differences between different treatments of 9 weeks or more. The time taken for sprouting to occur after the completion of each chilling treatment consistently decreased as the duration of the chilling treatment increased. In most cases, lower chilling temperatures lead to more rapid sprouting once plants were placed in the 18°C forcing conditions.When a simple model was fitted where the chilling temperature and duration of each treatment was described by a cumulative normal curve rising from zero to some maximum value (or potential) once adequate chilling had been received, we found that temperatures of 4 and 7°C provided only 83 and 59%, respectively, of the chilling accumulated per unit time at 1°C. ‘Coral Sunset’, an interspecific hybrid early flowering type, required the greatest amount of chilling to sprout consistently, while ‘Sarah Bernhardt’, a very late flowering type, required the least. Of the three cultivars, ‘Sarah Bernhardt’ also required the least amount of chilling to achieve its potential shoot and flower numbers, while ‘Monsieur Jules Elie’, a mid-season flowering type, required the most chilling to achieve the same end for these two variables. This suggests that the response to spring temperatures as well as chilling influences the time of flowering.  相似文献   

9.
The floral response of the type A avocado cultivars ‘Reed’, ‘Wurtz’, ‘Rincon’ and ‘Jalna’, and the type B cultivars ‘Bacon’, ‘Ryan’, ‘Edranol’, ‘Sharwil’ and ‘Hazzard’ was tested under growth-cabinet conditions of 17° C day, 12° C night, with a 12-h photoperiod and photon flux density of 400 μE m?2 s?1 (400–700 nm). Most of the flowers of all type A cultivars and the type B cultivar ‘Bacon’ had both a female and a male stage. None of the flowers of the other type B cultivars had a female stage but opened in the male stage only. Hand pollination resulted in some ovule penetration in the cultivars with female stage flowers. In those with only male-stage flowers, the pollen tubes grew no further than the style. Maintenance of fertility under low-temperature conditions during flowering appeared to be partly, but not entirely, linked to the type A flowering cycle.  相似文献   

10.
Summary

Photoperiod and temperature control of flowering in a number of perpetual-flowering or everbearing strawberry cultivars of widely varying pedigree has been studied in controlled environments. Flower bud initiation in the cultivars ‘Flamenco’, ‘Ridder’, ‘Rita’ and ‘Rondo’ was significantly advanced by long-day (LD) conditions at temperatures of 15°C and 21ºC; while, at 27ºC, flowering took place under LD conditions only. Some plants of the seed-propagated F1-hybrid ‘Elan’, raised at 21°C, also flowered under short-day (SD) conditions at 27°C, but reverted to the vegetative state after a few weeks when maintained under these conditions. When vegetative plants growing in SD at 27°C were transferred to LD conditions at the same temperature, they consistently initiated flower buds and started flowering after about 4 weeks. At such a high temperature, flowering could thus be turned on and off by switching between SD and LD conditions. This applied to all the cultivars studied. Also the cultivar ‘Everest’, which was tested only at 21°C, produced similar results. Night interruption for 2 h was effective in bringing about the LD response. At 9°C, flowering was substantially delayed, especially in ‘Flamenco’ and, at this temperature, flowering was unaffected by photoperiod. Runner formation was generally promoted by high temperature and SD conditions, but the photoperiodic effect varied between experiments. We conclude that everbearing strawberry cultivars, in general, whether of the older European-type or the modern Californian-type originating from crosses with selections of Fragaria virginiana ssp. glauca, are qualitative (obligatory) LD plants at high temperature (27°C), and quantitative LD plants at intermediate temperatures. Only at temperatures below 10°C are these cultivars day-neutral.  相似文献   

11.
In order to determine the proper time to harvest paprika pepper (Capsicum annuum L.) fruits to obtain maximum extractable color, two maturity indexes were evaluated. Most consistent results were obtained when fully shriveled fruits were harvested.Foliar applications of ethephon (50, 100, 200 and 500 ppm) were made on two cultivars, ‘Paprika-505’ and ‘Paprika-D.Z.’. Total extractable color and capsanthin content were determined using fully shriveled pericarp tissue. Some flower and leaf abscission was caused by treating plants with 500 ppm ethephon and leaves of plants treated with 200 or 500 ppm ethephon turned yellow. Ethephon stimulated ripening and increased the total extractable color and capsanthin levels of paprika fruits. ‘Paprika-505’ contained more total extractable color and capsanthin than ‘Paprika-D.Z.’ as a result of ethephon treatment.  相似文献   

12.
When grown in a glasshouse, flowering in Primula vulgaris ‘Aalsmeer Giant’ (yellow) and ‘Ducat’ (blue) was delayed with increasing temperature from approximately 12°C to 18°C. In addition, size of the first open flower and the number of flowering axillary shoots decreased, whereas the number of leaves and leaf area increased with the temperature increase. All temperature responses were greater in ‘Aalsmeer’ than in ‘Ducat’.When grown in growth rooms at 9°C, flowering in P. vulgaris ‘Aalsmeer Giant’ (yellow) was inhibited compared with 15°C. However, when 9 weeks of 15°C was applied to plants grown for 9 weeks at 9°C, the inhibition was overcome; longer periods of 15°C being no more effective. This indicates than an early stage of flower formation, probably the initiation, in Primula vulgaris is inhibited by 9°C, and not the further development of the buds towards open flowers.  相似文献   

13.
Summary

The effects of the length of chilling, chilling temperature and growing temperature on dormancy of asparagus crown buds and subsequent rates of spear growth were examined. The results showed that prior chilling enhanced bud break at low growing temperatures and stimulated the growth of spears.Thus, chilling should facilitate commercial production by hastening bud break and spear growth rates at lower temperatures. If sufficient chilling was given, the minimum temperature for rapid bud break was approx. 12.5°C for ‘Rutgers Beacon’ and ‘Jersey Giant’, and around 10°C for ‘UC 157’ and ‘Apollo’. The optimum chilling temperature appeared to be closer to 5°C than to 10°C or 2°C for ‘Rutgers Beacon’ plants grown at 12.5°C. Increasing the growing temperature had a significant effect on the relative spear growth rate (RSGR) in all cultivars. Prior chilling had no effect on the RSGR for ‘Dariana’ and ‘Apollo’; but, for ‘UC 157’, chilling plants at 5°C for 5 or 10 weeks increased growth rates at 12.5°C and at 20°C. These results demonstrate that release of bud dormancy and spear growth rates depended not only on the growing temperature, but also, at least in some cultivars at some temperatures, on the duration and temperature of chilling during the previous Winter.  相似文献   

14.
Glasshouse grown ‘Ace’ and ‘Nellie White’ Easter lily plants were subjected to different temperature regimes to determine temperature requirements during pre- and post-bloom development. Rate of leaf- and flower-bud development and stem elongation on the primary (mother) axis were directly proportional to the range of temperatures used (6–24°C), and were equally effective in predicting crop development. Scale initiation on the secondary (daughter) axis during pre-bloom phases was proportional to growing temperature, reaching maximum activity at 18°C in ‘Ace’ and at 12°C in ‘Nellie White’. The shift from scale to leaf initiation and development following anthesis was favored by 12 rather than 18°C with significant reductions in leaf initiation in both cultivars at 24°C. No difference in secondary meristem diameter occurred with temperature during pre-bloom, but large dome size was associated with 12°C or lower during the post-bloom phase. Primary scale weight increase (filling), reached a maximum 50 days following anthesis, and was greatest at 18°C. Secondary scale filling reached a maximum 80 days after anthesis at both 18 and 24°C. The secondary axis became increasingly responsive to sprout-inducing temperatures with increasing age and development. Fifty days after anthesis, 12 and 18°C were equally effective in sprouting ‘Ace’ bulbs, while 12°C was more effective with ‘Nellie White’. Early leaf senescence, associated with high (24°C) temperature, did not favor increased bulb size, daughter leaf primordia count and meristem diameter, or sprouting.  相似文献   

15.
The correlation between curd development and changes in endogenous hormones in the stem apex of cauliflower plants was investigated. In particular, plants raised normally were compared with equivalent plants given a 2-week cold treatment when 6 weeks old. Hormones were extracted and assayed from the two groups of plants from the time of seedling emergence until they were 10 weeks old. Hormone activity was high in the young seedlings but gradually decreased with age. Gibberellin activity increased in the apices after 6 weeks, with a further peak after 9 weeks, at which time the morphological changes associated with curd development were detected in a small proportion of the apices sampled from untreated plants. Both gibberellin peaks were enhanced by cold treatment. An increase in auxin activity was apparent in cold-treated plants, concurrent with the first gibberellin peak, but cytokinin activity was reduced by cold treatment. The physiological implications of these results are discussed.  相似文献   

16.
  相似文献   

17.
Rosa hybrida, cultivars ‘Samantha’ and ‘Cara Mia’, grafted on R. manetti, were subjected to 3 periods of 0° C night temperature during the 1978–1979 winter season, while the usual day temperatures were maintained. Significant increases in cane renewal were obtained after either a 23 December 1978 to 8 January 1979 or a 22 February 1979 to 23 March 1979 low-temperature treatment, but not after a 30 September 1978 to 30 October 1978 treatment. In the former 2 treatments, total non-structural carbohydrates were found to exceed 20% in leaves and 9% in stems. Plants in the October cold-night treatment and in the control treatment had lower carbohydrate levels. The cold night temperature treatments seriously upset timing of rose production for holidays, although more flowers were actually produced after the winter and late winter treatments than by the control plants. Possibly a shorter low temperature treatment could achieve the same effect with less disruption of the peak flowering-periods.  相似文献   

18.
A simple model is described which predicts when curds of any specified size will be produced. The model uses a quadratic relationship between the logarithm of curd diameter and accumulated day-degrees >0°C from curd initiation. Work in controlled environment cabinets showed a linear relationship between early curd growth rate and temperature between 8°C and at least 18°C, and that the base temperature for curd growth was 0°C. Data from samples taken after curd initiation are used to predict the number of day- degrees required for the crop to reach a specified size. This requirement is then converted into a predicted date by using long-term average weather data. This prediction can be updated progressively to take account of observed weather data where these deviate from average weather. Differences between the fitted relationships for different sites, years, transplantings and cultivars are discussed and data are presented showing the results of validation of the model.  相似文献   

19.
Fruit firmness, extractable juice, woolliness and browning of the mesocarp tissue in ‘Independence’ and ‘Flavortop’ nectarines stored at —0.5°, 3°, 5° and 7°C for four weeks were determined during ripening at 15°C. The firmness of both ‘Independence’ and ‘Flavortop’ during ripening decreased as storage temperatures increased. The percentage extractable juice after cold storage and during ripening varied considerably between cultivars and between the storage temperatures. The extractable juice of fruit stored at higher temperatures tended to increase during ripening, whereas fruit stored at lower temperatures tended to decrease first before increasing. At storage temperatures of —0.5° and 3°C both cultivars passed through a stage of woolliness during ripening, while less woolliness occurred after storage at 5° and 7°C. In both cultivars the percentage extractable juice during ripening was higher on average at storage temperatures of 5° and 7°C. Severe browning of mesocarp tissue in both cultivars occurred during ripening after storage at 3°C. The effect of fruit size on changes in firmness, development of woolliness and mesocarp browning in ‘Flavortop’ nectarines stored at — 0.5°C for four weeks and ripened at 15°C was also determined. Larger nectarines lost firmness more rapidly, woolliness occurred sooner and the mesocarp tissue was more prone to browning than smaller fruit during ripening.  相似文献   

20.
Summary

To control the bolting of Japanese bunching onion (Allium fistulosum L.) photoperiodically, the effect of photoperiods before, during and after vernalization on flower initiation and development and the varietal differences were investigated using the two mid-season flowering cvs Kincho and Asagi-kujo, and a late-season flowering cv. Cho-etsu. A long-day photoperiod (LD, 16 h) given before vernalization inhibited flower initiation. Especially, the bolting rate of ‘Asagi-kujo’ decreased by about a half, compared with the short-day photoperiod (SD, 8 h). The interaction between the effect of night temperature (3°C, 7°C, 11°C or 15°C) and the effect of the photoperiod (SD and LD) during vernalization was also investigated. In ‘Kincho’, LD did not affect flower initiation at 3°C, but inhibited flower initiation at 7°C, 11°C and 15°C. In ‘Asagi-kujo’, flower initiation was significantly inhibited by LD under all temperature conditions. This inhibitory effect was stronger at 11°C and 15°C than at 3°C and 7°C. In ‘Cho- etsu’, LD significantly inhibited flower initiation at 3°C and 7°C, and flower initiation rarely occurred at 11°C and 15°C. In this study, generally, LD during vernalization inhibited flower initiation in all cultivars. Thus Japanese bunching onion required a short-day photoperiod in flower initiation, which was stronger in ‘Asagi-kujo’ and ‘Cho-etsu’ than in ‘Kincho’. From these results, we conclude that low temperature and a short-day photoperiod complementarily induce flower initiation in Japanese bunching onion. Varietal differences exist in the requirement of low temperature and a short-day photoperiod: the primary requirement in ‘Kincho’ is low temperature and that in ‘Asagi-kujo’ is a short-day. After flower initiation, the early stage of flower development is day-neutral, and after the floret formation stage, a long-day photoperiod promotes flower development and elongation of the seedstalk.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号